The prevalence of obesity is increasing in most industrialized nations and is a primary cause of significant health complications, such as heart disease and cancer. At the source of the problem is our inability to control food intake when presented with excess food. It is critical that we understand how reward and motivation circuits of the brain regulate food intake and the nature of the dysfunction that causes obesity. While research has identified the hypothalamus as a critical mediator of peripheral metabolic signals, it is not clear how this is converted into the act of eating. This proposal focuses on a hypothalamic neuropeptide called melanin-concentrating hormone (MCH). MCH is produced in the lateral hypothalamus, a region that has been historically associated with rewarding behavior. Moreover, the MCH receptor is expressed in the nucleus accumbens, a region also studies for reward and drug addiction. Preliminary data is presented to demonstrate that MCH signals to the nucleus accumbens to regulated feeding behavior. Experiments are proposed to elucidate the cellular and molecular effects of MCH receptor signaling in the nucleus accumbens using genomic and phosphoprotein analysis. The results from the proposed experiments will shed light on mechanisms of MCH action in the nucleus accumbens while also serving to provide a better molecular explanation of how neuropeptides regulate complex animal behaviors such as food intak.